1. Field of the Invention
The present invention relates to a crank arm quick release device of a bicycle, and more particularly to a crank arm quick release device of a bicycle, wherein the pedal may be mounted on and detached from the crank arm easily and quickly.
2. Description of the Related Art
A conventional combination of a crank arm 20 and a pedal 30 in accordance with the prior art is shown in FIG. 5. The crank arm 20 has a free end formed with a screw bore 200. The pedal 30 has one end protruded with a rotation shaft 31 which has a free end formed with a screw portion 32 that may be extended through a washer 33, and may be screwed into the screw bore 200 of the crank arm 20. The crank arm 20 and the screw portion 32 of the rotation shaft 31 of the pedal 30 of the left side and the right side may form a reverse screw design which may prevent detachment of the pedal 30 when the pedal is stepped.
However, the crank arm 20 and the pedal 30 are combined by a reverse screw design. Thus, if the user rotates the pedal 30 in the opposite direction, the screw bore 200 of the crank arm 20 is easily worn out due to the wrong direction of rotation. In addition, the user has to screw the screw portion 32 of the rotation shaft 31 of the pedal 30 in the screw bore 200 of the crank arm 20, so that the assembly and disassembly thereof are inconvenient and slow.
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional combination of a crank arm and a pedal.
The primary objective of the present invention is to provide a crank arm quick release device of a bicycle, wherein the pedal may be mounted on and detached from the crank arm easily and quickly.
Another objective of the present invention is to provide a crank arm quick release device of a bicycle, which may be adapted to suit the pedal of a common bicycle, without having to make a new pedal, thereby saving cost of fabrication.
In accordance with the present invention, there is provided a crank arm quick release device of a bicycle, comprising:
a pedal, having one end protruded with a rotation shaft which has a free end formed with a screw portion having an outer thread;
a fixing threaded sleeve, having a center formed with a screw bore that may be screwed on the screw portion of the rotation shaft of the pedal, the fixing threaded sleeve having an outer wall protruded with two radially opposite locking flanges; and
a crank arm, having a free end formed with a mounting hole for insertion of the fixing threaded sleeve, the mounting hole of the crank arm being recessed with two insertion guide grooves for insertion of the two locking flanges of the fixing threaded sleeve, each of the two insertion guide grooves having one side formed with a locking recess which has a depth slightly greater than the thickness of the locking flange, and is communicated with the insertion guide groove, the locking recess of each of the two insertion guide grooves being distributed on a diameter of the mounting hole.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.